Polarity
Reversal First
Ring
CAS
(DTAS) DTMF/
FSK
Polarity
Reversal CAS
(DTAS) FSK
CAS
(DTAS) Wait For
ACK FSK
First
Ring FSK
OSI FSK
a) Bellcore/ETSI OnhookPost-Ring FSK
d) Bellcore OnhookFSK w/o Ring
f) Bellcore/ETSI OffhookFSK
c) ETSI OnhookPre-Ring FSK/DTMF
e) ETSI OnhookFSK w/o Ring
DTMF
b) ETSI OnhookPost-Ring DTMF
First
Ring
Figure: PHONE ADAPTER Caller ID Delivery Architecture
© 2004 Linksys Proprietary (See Copyright Notice on Page 2)
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